Sound reproducing device



Feb. 19, 1935. Q TICHENOR' ET AL 1,991,526

SOUND REPRODUCING DEVICE Filed July 9, 1932 4 Sheets-Sheet l INVENTORS CARL M. TICHENOR AND F102. B Y 0N C. BO0TH.

ATTORNEY 1935- C. M. TICHENORI ET AL I 1,991,526

SOUND REPRODUCING DEVICE Filed July 9, 1932 4 Sheets-Sheet 2 INVENTORS CHRL M.TICHENOR. "ND BY$N C..BOOTH.

ATTORNEY Feb. 19, 1935. Q TICHENOR ETAL 1,991,526

SOUND REPRODUC ING DEVI CE Filed July 9, 1932 4 Sheets-Sheet 3 I fl'rr-- FIG. 5

IN ENTO S CARL MTMCHENO HND BYRON C. BOOTH ATTORNEY Feb. 19, 1935. c TICHENQR ETAL 1,991,526

SOUND REPRODUC ING DEVI CE Filed July 9, 1932 4 Sheets-Sheet 4 FiG.7. A

FIG.8

INVENTORS 0/! RL P7. TICHENO'R ma/v 0 BOOTH ATTOIQNEY AND , especially easy to assemble and economicalto a cylindrical casing 5L Patented Feb. 19, 1935 a T i v 1,991,526

- UNITED STATES R EN C Carl M, Ti chenor, Muskegon, and Byron C. Booth,

Muskegon Heights, Mich.

' Application July 9, 1932, Serial No. 621,672

' 2 Claims. (01. ris -115.5)

Our invention relates to loud speakers and has; Figure '3 is a central sectional view of the especial relation to those of the moving coil type. speaker shown in Figures 1 and 2. One object-f our invention is to provide a loud Figure 4 isa central sectional view of speaker speaker in which the-diaphragm 'maybe conembodying a modified form of the invention. veniently adjusted. during manufacture to vary Figure5 is a 'sideelevationalview of the speaker 5 the location of the voice coil longitudinally of shown in'Figure i. Y r. the core, whereby the voice coil may be accurately Figurefi is a"sje'ctional View taken on the line located in the air gap. VI-VI o'f- FigureB; and 1 Another object of our invention is to provide a Figures 7 "and B" are central sectional views of mounting. for aloud speaker of the type Ynenother, speakers embodying modifications of the 10 tioned,=which.supports the diaphragm freely my invention: i i 7 an unrestrained and undeformed condition, Figures 3, 4, 6, 7 and'8'are on an enlarged scale. whereby itis adapted to effect a more faith- Referring in more detail to the drawings and ful translation of the voice currents into sound. particularly to-Figures 1, 2 and 3, a diaphragm 1' l5 A-further objectof our invention is to provide may be of the usual conical form, and may be an especially eflicient loud speaker of the type i secured by anadhesive atitsperiphery between mentioned. a a cushion 2 and a rigid support. 5 V 1 Afurther object of our invention is to provide The support comprises a rim Sand a plurality a loud speaker of the type mentioned which is of arms 4 whichar'e preferably cast integral with manufacture. I 1 A core 6 has at one end a flange 7 fitting A further object of our invention is to provide closely within thejc'asing and extending through a loud speaker ofthe movable coil type in which a field coil 8 which preferably is wound directly anadjustment is provided between the support on the core so as to' reduce as much as possible for the periphery'of thediaphragm, orcone, and losses of magnetic flux induced by the coil. A 25 the pp for the Spider at the apex of the bucking coil IO may be interposed between the cone, whereby variations in the altitudes of cones core 6 and the flange 7. as experienced in quantity manufacture maybe A pole piece 11, which may be in the form of compensated for. .a ring, 'is secured to a second flange 12 on the A further object of the invention, as eX- core 6 by means of a plurality of spacers'l3 which 30 emplified in one of its various embodiments, is may be of brass or othermaterials not adapted to provide a movable coil type of speaker in which to conduct the magnetic flux The spacers 13 a pole piece surrounding the core is adjustable have reduced ends riveted in holes 13 in the relative to the rest of themagnet longitudinally pole piece '11 and the flange 12. h of the axis'of the core so that it may be accurately The core 6, the casing 5; and the pole piece 11 located with respect' tothe voice coil. constitute a magnet.

A further object of our invention is to provide The pole piece 11 has an opening 14 therein dea lel'ldlspeekel that pe y pted for fining an air gap which receives a voice coil 15 q n y m n r y i of such precision mounted onxa collar 16 secured to the diaphragm that the ,voi'cecoil mayadvantageously be made 1. A yieldable support 17; which may be of the 40 of a sir'l'gle layer of tllms of L spider typewell known in the art, secures this A still further ob ect of our invention is to portionof t diaphragm t a nipp1e 13 on t provide a Speaker of the movable coil type in core 6, a screw 20 holding the support 17 on the which a pole piece surrounding the core has a nipple threaded relation to the magnet so that the for- In assembling the parts the pole piece 11 is mer ma be ad'usted alon the axis of'the core to a deified poJsition withg respect to the voice, preferably secured to the flange 25 and the coils coil I 8 and 10 woundon the core. The diaphragm 1 Other ob'ects and advanta es will a car as the be secured to the Support as Separate descriptionlproceeds g pp which may then be assembled with the core 6 and 50 In the accompanying drawings, e' 1 is a associated parts. The support may be shifted Side 1 t 1 View of a l Speaker embodylongitudinally of the core 6 until the voice coil 15 mg the invention, is located properly in position in the air gap. The

Figure 2 is a sectional View on the line 11-11 flexibility of the pp r 7 p s hi p of Figure 1 V ment ofithe voice coil. The support is then se- 55 cured in position by a set screw 21 or other suitable means. I

In the manufacture of speakers the accurate positioning of the voice coil in the air gap isa matter of extreme importance as it is desired that the greatestdensity of flux be directed through the windings of the coil for most eflicient operation.

When there-is a lack of uniformity in the altitudes of the cones the adjustability of their pe ripheries permits the proper placement of the voice coil without distorting the supportsor spider 17, or straining, or many way limiting the free movability of the diaphragms in the operation of the speakers. g

It will be understood that the cost of manufacture of the described speaker is especially low. 7

The assembly of parts is especially easy and they are quite easy and simple to make. The casing 5 and the support may be a simple unmachined casting or if the greatest accuracy is desired the casing 5 may be bored at the surfaces 22 and 23 where it engages the pole piece 11 and the flange '7 respectively.

In the modified form of loud speaker shown in Figures 4, 5 and 6 a magnet comprises a core 24 and an outer wall 25 preferablyin one piece, the wall surrounding a field coil. 26 and a bucking coil 27. Apole piece 28 fits tightly within the wall and is thus held in place. The support 30 for the periphery of the diaphragm is similar to that previously described and is preferably integral with a casing 31 which is adjustable longitudinally of the magnet in the same manner as the support in Figures'l, 2 and 3 and engages the magnet throughout spaced circular areas 32 and33. A set screw 34 holds the casing 31 in adjusted position. A spider or support 35, is secured to the apex of the cone 36 and by means of screws to a plurality of bosses 37 on the pole piece 28.

It will be apparentthat when the casing 31 is shifted longitudinally, the position of the voice 'coil 38 will be adjusted'as in the previously described modification. I V

The polepiece 28 and the outer wall 25 of the magnet are preferably machined-on their.surfaces which meet at 40 and these parts are assembled by merely pressing the former into the opening provided by the latter.

It will be apparent that with our invention, extreme precision is obtainable. In the embodiment shown in Figure 7 this is taken advantage of' and the voice coil 41 instead of being made of two layers .of coils, as has been common heretoiore, consists of a single layer of a length greater than the voice coils now used. The pole piece 42 also is made quite thick and the air gap 43 is very small, consequently'the' speaker is highly eificientyet, owing to the precise location of parts, there is no rubbing of the voice coil when 1,991,526 V operated, notwithstanding its length. With the exceptions mentioned and also the. provision 01. an internal spider 44, modification shown inFigure 7 is the same as that shown in Figures 4, 5 and 6. I

The embodiment shown in Figure 8 is similar to that shown in Figures 4, 5 and 6 except that an internal spider 45 is provided and the pole piece .46 is threaded in the outer wall of the magnet which is preferably integral with a support 47 for the diaphragm or cone 48.: Sockets 50 are provided to receive the ends of a wrench for aq justing the position of the pole piece 46 in correspondence with the location oi" the voice coil.

, Preferably also a cushion 47 such as a ring of Our invention is not limited to 'the'specific-j details of the constructions illustrated and depscribed which may be modified extensively with out departing from the spirit of the invention,

for instance, the casing 57in Figures 1 2i'and'3 need not be cylindricalbut may be rectangular: or of other desired shape andin fact need not 'entirely surroundthe field coil. A substantial range of equivalents is contemplated within the scope of the appended claims.

We claim: i V

phragm, a core having one end adjacent said;

diaphragm, a field jcoil surrounding saidcore, a pole piece permanently secured to said c0re'adjacent said end thereofand magnetically connected to the otherend, said piece having'an, opening receiving said core and defining air gap receiving the first, mentionedcoil, said support being adjustable with respectto said'piece in a direction along'theaxis of said core to locate said first mentioned coil accurately in said air gap and releasable means for;securing said support with respect to said piece.

2. In a speaker of the movable coil-type; the

combination of a diaphragm, a coil on said diaphragm, a support for the periphery of saiddia-.

phragm, a magnet comprising a core having one end adjacent said diaphragm, a field coil surrounding said core, a pole piece permanently secured to said core adjacent said end thereof and having an opening receiving said core and de-y fining'an air gap receiving the first mentioned coil, said support having a portion betweenxandengaging said pole pieceand the other endot', said core and constituting aportion of said magi net and being adjustable longitudinally to locate said first mentioned: coil accurately in said air 1 

